# File lib/phusion_passenger/platform_info/binary_compatibility.rb, line 59
        def self.ruby_extension_binary_compatibility_ids
                ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : "ruby"
                ruby_ext_version = RUBY_VERSION
                if RUBY_PLATFORM =~ /darwin/
                        if RUBY_PLATFORM =~ /universal/
                                ruby_arch = "universal"
                        else
                                # Something like:
                                # "/opt/ruby-enterprise/bin/ruby: Mach-O 64-bit executable x86_64"
                                ruby_arch = `file -L "#{ruby_executable}"`.strip
                                ruby_arch.sub!(/.* /, '')
                        end
                elsif RUBY_PLATFORM == "java"
                        ruby_arch = "java"
                else
                        ruby_arch = cpu_architectures[0]
                end
                return [ruby_engine, ruby_ext_version, ruby_arch, os_name]
        end